Patent GB-1257111-A (GB)
IPC: C07C45/58
Filed: 1969-09-11
Abstract: 1,257,111 Acetylenic aldehydes. A.ESCHENMOSER. 11 Sept., 1969 [19 Sept., 1968], No. 44959/69. Addition to 1,211,697. Heading C2C. Acetylenic aldehydes of the formula wherein R 1  and R 3  and/or R 2  and R 3  are directly bonded to each other and R 1  and R 2  may also be directly bonded to each other, R 1 , R 2  and R 3 , which may be the same or different, when bonded to one or two of the other groups R 1 , R 2 , R 3  each representing a bi- or tri-valent organic radical respectively or R 1  and R 2  when not bonded to any of the other groups R 1 , R 2  and R 3  each representing a hydrogen atom or a monovalent organic radical are prepared by fragmenting an imino-aziridine of the formula (wherein R 4 , R 5 , R 6  and R 7  which may be the same or different each represents H, alkyl, alkenyl, cycloalkyl, aryl, alkoxycarbonyl, CN or NO 2  but not all can be H together, or any two or more of R 4 , R 5 , R 6  and R 7  together with the carbon atom(s) to which they are bonded form a ring), with simultaneous evolution of molecular nitrogen. Fragmentation can be achieved thermally or photo-chemically, possibly under the very conditions under which the starting imino-aziridines are formed, e.g. when the corresponding carbonyl compounds are reacted with amino-aziridines. Preferred starting materials are (a) ring compounds with the epoxide group on adjacent ring carbon atoms and the carbonyl group in a side chain in α-position to the epoxide group, which give products which are open chain acetylenic aldehydes or cyclic compounds in which the CHO group and the triple bond are separately located in 2 side chains; and (b) cyclic compounds in which the epoxide group and the carbonyl group are both located in the ring, which give products as in (a). In Examples (1) phenylethylene glycol dimesylate (from the diol and mesyl chloride) is condensed with hydrazine to give 1 -amino-2-phenylaziridine (acetate also described), this with 1,2-epoxy- 1 -propionylcyclohex-4-ene gives a crude hydrazide (iminoaziridine) and this on heating at reduced pressure gives non - 2 - en - 6 - yn - 1 - al and non- 3 - en- 6-yn-1-al which are separated by gas chromatography; (2) hydroxyurethane and 2-nitrobenzenesulphonyl chloride are condensed to give a product C 2 H 5 OOCNHOSO 2 R (where R is 2-nitrophenyl), this is reacted with 7-azabicyclo- [4.1.0]heptane to give the N-ethoxycarbonylamino derivative, this is hydrolysed to 7-amino-7- azabicyclo[4.1.0]heptane, this is reacted with 1 -formyl - 1,2 - epoxycyclopentane (prepared by peroxidation of 1-formyl-cyclopent-1-ene) to give a crude hydrazone (imino-aziridine) and this on gas chromatography fragments to provide hex-5-yn-l-al; (3) 2-methyl-2,3-epoxycyclohexan-l-one and l-amino-2-phenylaziridine are condensed to give a crude hydrazone (iminoaziridine) and this on heating at 150‹ C. and 60 mm. Hg gives styrene and hept-5-yn-l-al; (4) 1 - acetyl - 1,2 - epoxy - cyclopentane (from 1 - acetyl - cyclopent - 1 - ene) and 1 - amino-2- phenylaziridine give via a crude hydrazone (amino-aziridine) the same products as (3); and (5) 2,3-epoxycyclohexanone and l-amino-2- phenylaziridine give via a crude hydrazone (imino-aziridine) hex-5-yn-l-al. Other products prepared are 3#-acetoxy-16-oxo-16,17-seco-#<SP>5</SP>- pregnen-17(20) -yne and its dimethyl acetal; 3 - methoxy - 16 - oxo - 16,17 - seco - #<SP>1</SP>'<SP>3,5</SP>'<SP>(10)</SP>-19- norpregnatrien - 17(20) - yne; 3 - oxo - 17#- acetoxy - 2,3 - seco - 5α - androst - 1 - yne; 1- formylmethyl - 3 - ethynyl - 4,4,8 - trimethylbicyclo - [3.3.0] - octane, dec - 4 - yn - 1 - al; undec - 4 - yn - 1 - al; non - 4 - yn - 1 - al, dodec - 4 - yn - 1 - al; pentadec - 4 - yn - 1 - al; and hept-4-yn-l-al.